This study questioned whether children's relative inability to use the two cerebral hemispheres independently contributes to their difficulty with the simultaneous execution of conflicting tasks. Two naming tasks involving the identification of upright and inverted letters were employed; conditions differed according to how the letter pairs were distributed within or between visual fields and whether tasks which required conflicting processing were or were not physically separated. It was predicted that (1) division of inputs between the hemispheres would be advantageous only when one hemisphere received upright letters and when the other hemisphere received inverted letters, and (2) the extent to which the hemispheres independently process information would reach a peak during early adolescence. These hypotheses were confirmed in a sample of 120 children. When conflicting inputs were directed to different hemispheres, older children (12- and 14-year-olds) named more items when the inputs were presented bilaterally than when they were presented unilaterally. Younger children (10-year-olds) displayed no advantage for bilateral presentations regardless of whether conflicting tasks were projected to the same hemisphere or different hemispheres. The fact that 10-year-olds did not benefit from division of conflicting inputs between the hemispheres was interpreted as a symptom of their relative inability to use the hemispheres independently. (Author/RH)